function y = createElementContainer()
y = struct( 'stress',[0 0 0]',...
        'constitutiveMatrix',[],...
        'Dnn',0,... %normal stifness coefficient at crack surface
        'Dss',0,... %shear stifness coefficient at crack surface
        'mu',0,... %friction coefficient at crack surface
        'ef',0,... %damage parameter
        'ft',0,... %tensile strength
        'Gf',0,... %fracture energy
        'isActivated',1,...
        'isCrack',0,...
        'isOpening',0,... %couple with isLoading to indicate load/unload state
        'isLoading',0,...
        'isSticking',0,... %indicate sticking mode
        'isSliding',0,... %couple with isLoading to indicate damage grows/not grows
        'A',[],...
        'H',[],...
        'e',[0 0]',... %separation vector
        't',[0 0]',... %traction vector, used for opening mode
        'ttilde',0,... %postulate g(0) at crack initiation to ensure consistency
        'f',[0 0]',... % = dF/detilde * detilde/de
        'fs',[0 0]',... %used for sliding mode, fs = [mu s]'
        'gamma',0,... %damage parameter
        'gamma_old',0,... %history damage parameter
        'crack_normal',[],...
        'X1',[],...
        'X2',[]);
end
